ALLNIC AUDIO L-10000 OTL

The L-10000 OTL/OCL (Output Transformer-Less/Output Capacitor-Less) is a triple gain stage, remote controlled, line-stage preamplifier, without transformers or capacitors in its single-ended signal path.

• OTL, OCL Direct Coupled preamplifier
• Two SEPP 300Bs output
• True Dual Mono design
• 61-step Silver Contact Constant Impedance attenuator

Immerse yourself in the original recorded space. The L-10000 OTL/OCL (Output Transformer-Less/Output Capacitor-Less) is a triple gain stage, remote controlled, line-stage preamplifier, without transformers or capacitors in its single-ended signal path. It uses the 300B direct-heated, single-ended triode as its directly coupled output power tubes; i.e., there are no output transformers on the single-ended (unbalanced) outputs, so the 300Bs communicate the signal directly to the connected power amplifier or amplifiers. The 300B has justly won the reputation of being a superb output tube in single-ended amplifiers, and in the L-10000 OTL/OCL preamplifier they fully reveal their inherent accuracy and beauty.

In common circuits, output capacitors or output transformers are required to separate the AC music signal from the DC operating potential. If this is not done, the latter will destroy the power amplifier, the loudspeakers, or both. However, these two coupling devices also introduce their own influences on the transmission of the musical signal, adding their own character (colouration), increasing distortion, and consuming small signals, all as predicted by physical efficiency theory. In addition, they also limit signal dynamics. For these reasons, the elimination of output transformers and capacitors has been considered the best solution for the design of the most accurate amplifiers. Removal of these two coupling devices from the signal path achieves the best results possible:

• No colouration of the musical signal
• Extremely detailed expression, natural harmonics and subtle musical decay
• The lowest possible distortion
• The widest musical dynamics

In the L-10000, there is no coupling device between the preamplifier and the power amplifier; that is, the final gain/output tubes are directly connected to the power amplifier. Thus, the benefits listed above are fully present in the Allnic L-10000 preamplifier.

Some circuit experts might be concerned about DC potential in the music signal in an OTL/OCL design. However, the chance of this problem occurring can be 100% reliably eliminated by doing away with the potential for DC in the signal path. To do this, Allnic uses a “floating power supply circuit”, a design which deals with the theoretical issue by simply not creating any DC potential in the first place.

The L-10000’s OTL/OCL circuit is basically SEPP, “Single-Ended, Push-Pull”, so a “cancellation circuit” is required to adjust the balance of signal between the upper and lower power output tubes’ input grids. Allnic uses an extremely sophisticated “Active Balanced Positive and Negative Feedback Circuit”, in which the 6AN8 pentode perfectly controls the circuit’s operation with extremely low distortion and incredible speed.